1. Technical Field
The present invention relates to an image processing device and an image processing method, and in particular an image processing device and an image processing method which correct a face image.
2. Related Art
When an image, such as a picture or video, contains the face of a person, in many cases, the face contained in this image could be a part that attracts the attention of a viewer for the image. Conventionally, there has been a technique of correcting or adjusting a face image so as to enhance the appearance of the face contained in the image.
For example, Patent Document 1 discloses a technique of: extracting contours of upper and lower lips; identifying a part surrounded by the inner contours of the detected upper and lower lips as a part corresponding to the teeth; and adjusting the lightness of the part corresponding to the teeth. For example, by lightening pixel values in the part corresponding to the teeth, the appearance of the face can be enhanced. In the technique of Patent Document 1, the contour of the lip is detected from the difference in brightness value among individual pixels within the image, in order to identify the part corresponding to the teeth. In more detail, a plurality of detection lines extending in a vertical direction (a direction along the height of the face) are defined in a mouth region, then the difference in brightness value among the pixels is checked along each detection line, and points at each of which the brightness value is relatively greatly differs are determined as contour points of the lip. Then, from a spatial distribution of the determined contour points, contour points that correspond to the outer and inner contours of each of the upper and lower lips are identified, and a region surrounded by the inner contours of the upper and lower lips is identified as the inner part of the mouth. Finally, it is believed that a region corresponding to the teeth is present in it.
Patent Document 1: Japanese Unexamined Patent Publication No. 2009-231879 (published on Oct. 8, 2009).